Frequency determining unit



ay 1946 5. A. BOKOVOY 2,399,908

' FREQUENCY DETERMINING UNIT Filed July 20, 1944 T INVENTOR'. JflMUfL 4. 50mm) I BY A TTORIVEY Patented May 7, 1946 umrsosmrssi PATENT OFFICE 2,399,903?

FREQUENCY DETERMINING UNIT I Samuel Alerander Bokovoy, Verona, N. 1;, assign- 4 or to Federal Telephone and Radio Corporation,

New York, N. Y., a corporation of Delaware Application July 20,1944, Serial No. 545,847

7 Claims. (01. 171-321) v .This invention relates in general to oscillator or resonator unitsfor crystal controlled oscillator circuits and consists of an improved design and structural arrangement adapted for th'e'production of a materially simplified and economical unit ofiering important advantages over constructions as heretofore employed. The features thereof are particularly valuable as incorporated in the smaller types 01' unit assemblies of the so called bottom loading type employing a protective cover formed with an internal socket or recess for the reception of the crystal'and associated electrodes and spring and a base member for assembly therewith carrying opposite contacts to engage an electrode at one side and at the opposite side with the spring associated with the opposite electrode and with the base provided with the usual terminal pinsf- In oscillator units of the type to which this invention particularly applies, dilliculties have heretofore been encountered in theassembling of the crystal and associated parts including the oppo---' I site electrode plates .and in returning them in their proper co-relation. While in certain forms of structure the objectionable difiiculties of preperly assembling have been partially overcome by the employment of a separable frame member or chase in which the crystal and electrodes areini-v cillator unit structure.

s with the base and cover plates partially separated to illustrate the simultaneous partial withdrawal fective to impart the mounting pressure on the electrodes and crystal, an added diiliculty is presented to the withdrawal of the parts. This difficulty is enhanced in the desirable small unit structures. a

The described and other features and advantages of the present invention will be more fully understood by reference to the accompanying drawing wherein like reference characters are applied to the corresponding parts in the several views."

In the'drawing':

Fig. Us a view in vertical, longitudinal section showing an approved embodiment of the features of the invention in a resonator unit structure adapted for'the protective mounting of a piezoelectric crystal element in the customary manner for thickness oscillation.-

Fig. 2is a top plan view of the-base member of Fig. 1 showing the contact members assembled therewith.

' Fig. 31s a central vertical-cross sectional view taken on line 3-3 of Fig. 1 of the assembled os- Fig. 4 is a view generally similar to Fig. 3 but of the separable crystal and electrode elements.

Referring now in detail to the disclosed and preferred embodiment of the invention. l indicates a base portion or member of molded insulating material. This base portion. shown of rectangular form, has rigidly secured thereto ionframe member and the objections of its use is accomplished with a desirable improved compactness for reduction in. size and moreover in a man ner to insure of an improved removable relation and retaining of the parts. In addition there is produced a related structural arrangement wherein uponwithdrawing or separation of the base from the cover there is simultaneously eilected a partial withdrawal of the contained parts including the crystal electrodes and compression spring so as to efiect their partial removal into a projected position thereby to facilitate grasping by the fingers to expedite removal. This is an important advantage in the disclosed type of assembly wherein the crystal is supported for thickseparable parts are desirably fully received within the socket of the cover, including a spring efgitudinaily spaced and aligned mounting pins 2 which extend vertically through the insulating body of'the base. In the customary manner they are rigidly secured by being molded in the. material of the base portion. To the upper or inwardly directed'surface or the base member there mounting pins 2 as by welding for electricalconnection therewith. In cooperating relationwith the base there is provided a cover member I of molded insulating material formed with an internal and downwardly open rectangular socket 8 adapted, in conjunction with the base portion.

to provide a hermetically sealed protective enclosure for the crystal and associated mounting parts. To the latter end, provision is made for securing the coverv and base members consisting of the securing screws 1 threaded into cover apertures 8 and passed through base apertures usguideway grooves i2. tend inwardly from the open end of the socket permit of securely fastening of the cover and base members with the interposed elastic sealing In the unloading of the insert parts of the device on its disassembly further advantage and washer Ill. The cover socket is of elongated rectangular formation having parallel vertical side and end walls and having its inner wall surface formed with spacing shoulders or bosses II. It is further formed with its vertical side walls provided with vertically extending, centrally aligned,

These are formed to exto a position midway of its depth and with the inner ends of thegrooves tapered at l3 so that the opposed side walls of the respective grooves are at their innermost portions upwardly and inwardly inclined.

The crystal element is shown at H of the customarily employed rectangular plate form and in the assembly is received within the socket and positioned between the opposite electrodes is likewise of rectangular plate formation and of a character to make proper electrical and cooperating contact with the face of the crystal in a manner to avoid damping of the vibrations. The outerface of one of the electrodes, the ieft hand electrode as here shown, is engaged by the inner face of one of the resilient base contact plates 3 .while the opposite or right hand electrode is engaged by the inner enlarged turn it of compression coil spring II which is positioned to effect a. pressure clamping or supporting of the crystal element. The vertical dimensions of the crystal and associated electrodes and washer are such as to be rather closely confined between the bosses I i of the cover and the upper surface of the base portion thereby to insure ofaccurate positioning and retention of these elements in cooperating relation. The upper surface of the base portion is formed with an inward recess or groove is which in its dimensional relationship to the supporting flanges of the resilient contacts insures the proper alignment ofthe contact plates through assembling of the contact plateswith the block and terminal pins 2. Also as best shown in Fig. 2, in the forming of the groove l8 spaced bosses is are provided in substantially vertical alignment with the bosses II to cooperate therewith in the positioning of the insert members.

The improved facility of, and other advantages incident to, the loading and unloading of the insert elements or assembling of the device will be best understood by reference to the Figs. 3 and 4. In the loading of the unit the crystal the entry or guideway grooves I2.

facility are obtained. This will be appreciated by reference to Fig. 4 from which it will be noted that as the base element is withdrawn from its assem bled position, during the initial period of its movement, the insert elements will be retained in pressure engagement with the opposite contact plates 3 in a manner whereby they will be likewise partially withdrawn from the socket into an accessible exposed position. They are released from such withdrawing pressure only after the ends of the contacts 3 are fully received within They are accordingly' more readily removed for inspection or replacement.

Additional advantages presented by the improved structu're as described include facility in accommodating diiferent sizes of crystals by varying the dimensions of the socket, a material reduction in the parts with resulting economy in required tooling and stocking of parts together with reduction in tolerances required. The contact plates and also the pin terminals 2 may desirably be made of nickel silver so as to permit of their being soldered or welded without flux resulting in further advantage of avoiding loosev flux and acid influence. Other modifications may be made therein without departing from the scope of the invention as defined in the claims. As illustrative, in place of the securing screws for atelement with the electrode plates positioned at each side thereof, are dropp d into position or inserted within the cover. The coil spring, deslrably of the conical form as shown, is then inserted to hold the electrodes and crystal together. The resilient contact plates 3, assembled with the base, are then engaged or-inserted within the grooves II of the cover member 5 and as they are advanced inwardly will engage the outer surfaces of the left hand electrode and the spring l1. As a result of the camming action of the tapered portions iii of the groove, contact plates 3 will be inwardly deflected to establish-a final assembly and resilient clamping of the crystal as the base and cover are moved into homed inight'cause displacement of the spring from its intended position.

taching the base to the cover as shown it is proposed that a polystyrene cement may be employed between the engaging surfaces ofthe base and cover thus to provide for hermetically sealing with the elimination of the screws.

What is claimed is:

1. A frequency determining unit of the eharacter described comprising a container formed to provide a socket for the reception of aresonator element, a crystal element and opposite electrodes associated therewith adapted to be received within the container, said container being composed of a cover. member and a separable base for assembly therewith, contact elements carried by the base and said cover being provided with guide means formed to effect deflection of the contacts into a contacting position upon assembling of the parts.

2. A frequency determining unit of the character described comprising a container formed to provide a socket for the reception of a resonator element, a crystal resonator and opposite elecmembers.

3. A frequency determining unit of the character described comprising a container formed to provide a socket for the reception of a resonator element, a crystal resonator element having opposite electrodes associated therewith received within the socket, a resilient element positioned to impart a holding pressure on the electrodes and crystal element, said container being composed of a cover member having a bottom opening socket and a base member fitted to close the socket, said base being provided with terminal pins for plug in connection and with projecting resilient contacts connected with the pins, the socket being formed with guideway grooves in tainer formed to provide a socket for the recep-' tion oi a resonator element, a crystal resonator element having opposite electrodes associated therewith positioned within the socket, a coil spring positioned to impart a holding pressure on the electrodes and crystal element, said conprovided with terminal pins for plug in connectainer being composed of a cover member having a. bottom opening socket and a base mem-- ber fitted to close the socket, said base being provided with projecting resilient contacts and the cover socket being formed with guideway grooves in its side walls positioned'for registration with the base contacts and formed at their inner ends with deflecting surfaces positioned'to be engaged by the contacts prior to 'full assembly position and said deflecting surfaces being positioned to at least partially underlie the spring.

5. A frequency determiningnnit oi the character described comprising an insulating container for the reception of a resonator element,-

for clamping or the insert elements between it and the opposite contact.

6. A frequency determining unit of the character described comprising an insulating container for the reception of a resonator element,

said container being composed of a cover memher having a bottom opening socket and a base member fitted to close the socket, said base being tion and with projecting resilient contacts connected with the pins, said cover socket being formed with guideway grooves in its side walls positioned for registration with the base contacts and having inward deflecting surfaces to be en.- gaged. by the contacts prior to full assembly, a crystal resonator'element, oppositely positioned electrodes and a resilient element'adapted to be inserted within said socket, one of said electrodes and said resilient element being engaged by the contacts when inwardly deflected for clamping the insert elements.

. "7. A frequency determining oi the character described comprising an insulating container for the reception or a resonator element, said container being composed of a'cover member having a bottom opening socket and a base said container being composed of a cover memher having a bottom opening socket and a base member fitted to close the'socket,'said base be-' ing provided with terminal pins for plug in connection and with projecting resilient contacts connected with the pins, said contacts having bases positioned within a socket in the basemember formed to determine the position of the contacts, said cover socket being formed with guideway grooves in its side walls positioned for registration with the base contacts and having inward deflecting surfaces to be engaged by the contacts in an intermediate assembly position, a crystal resonator element and oppositely inserted electrodes positioned within the cover socket and a resilient element positioned to impart a holding pressure on the electrodes and crystal elementand to be engaged by one of the contacts member fitted to close the socket, said base being provided with terminal pins for plug in connection and with projecting resilient contacts connected with the pins, said contacts being mounted within a socket in the base member formed to determine the position of the contacts, said cover 

